This invention relates to improvements for electrical circuits, particularly in relation to electrical circuit boards for use in electrical devices.
Electrical circuit boards (often referred to as printed circuit boards or PCBs) are used in virtually all electrical devices to support the electrical components thereof and the electrically conductive pathways therebetween. The pathways (commonly referred to as “tracks” or “traces”) are typically etched from copper sheets which are laminated onto a non-conductive planar supports, e.g. fibreglass sheet. Layers are then built up one on top of the other and electrical connections made between the pathways of each “layer”, as desired, in order to provide the required electrical circuitry between the electrical components.
Printed circuit boards or PCBs provide mechanical support for the electrical components and the pathways of copper due to the rigidity and strength of the fibreglass support layers and are thus the preferred choice for the electrical circuitry and component support for most electrical devices worldwide. Their inherent rigidity, however, and thus their lack of flexibility, can often be a disadvantage, as it can render their integration in certain products difficult.
It has therefore been proposed to substitute the rigid fibreglass support layers of the PCB with a flexible material to provide a circuit board. Such as ‘board’ can be used in devices which require the circuit board to be capable of being distorted in three dimensions, which is not possible with standard PCBs. However, the current manufacturing methods and the resulting ‘boards’ have some performance an reliability issues.
According to a first aspect of the invention we provide an electrically conductive pathway including a plurality of pathway sections which are connected end to end, and wherein each pathway section includes:                a) a first elongate part;        b) a second elongate part;        c) a first resiliently flexible part connected at one end to an second end of the first part and connected at its opposite end to a first end of the second part; and        d) a second resiliently flexible part connected at one end to an second end of the second part and connected at its opposite end to a first end of the first part of an adjacent pathway section.        
According to a second aspect of the invention we provide an electrically conductive member including a pathway according to the first aspect of the invention.
According to a third aspect of the invention we provide an electrical circuit board including an electrically conductive member according to the second aspect of the invention.
According to a fourth aspect of the invention we provide a method of manufacturing an electrically conductive member, the method comprising the steps of:                positioning a layer of electrically conductive material adjacent a substrate layer;        increasing the temperature of the electrically conductive and substrate layers to a predetermined temperature;        applying pressure to the electrically conductive and substrate layers so as to urge the layers towards each other;        holding the electrically conductive and substrate layers at said temperature for a predetermined time period;        cooling the electrically conductive and substrate layers to a predetermined temperature;        removing unwanted areas of the electrically conductive layer to provide at least one electrically conductive pathway connected to the substrate.        
Further features of the various aspects of the invention are set out in the claims appended hereto.